TECHNIQUE

Intraosseous Catheterisation and Administration of Medication in Rabbits (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords IO catheterisation
Description Note: Techniques used in wild lagomorphs
  • While most veterinary procedures described for use in domestic rabbits can also be used in wild lagomorphs, it is much more likely that sedation or anaesthesia will be required to carry out such procedures in these animals.
Sites
  • Greater trochanter of the humerus (B601.2.w2, B606.17.w17, J213.9.w1)
    • This is the easiest site for intraosseous catheterisation. (B600.3.w3)
    • Draw an imaginary straight line from the greater trochanter of the humerus to the elbow joint and then insert the needle through the greater trochanter and direct it along the imaginary line until the medullary cavity is penetrated. (B600.3.w3)
  • Tibial crest (B601.2.w2, B602.14.w14, B606.17.w17, J213.9.w1)
    • Insert the needle just caudoproximal to the tibial crest, directing it towards the medial aspect of the tibia to penetrate the medullary cavity. (B600.3.w3)
    • If the needle is inserted along an imaginary straight line from the tibial crest to the hock joint, it will miss the medullary cavity and just end up in the cortex because the lateral wall of the tibial cortex actually curves medially. (B600.3.w3)
  • Greater trochanter of the femur (B601.2.w2, B602.14.w14, B606.17.w17, J213.9.w1)
    • This is the least satisfactory site for administering intraosseous fluid therapy because there is a well-developed trochanteric fossa that can be seen when the femur is viewed caudally. The intraosseous catheter must pass through this fossa (penetrating three layers of cortical bone) to enter the medullary cavity. (B600.3.w3)
    • This is easily palpated; the spinal needle is passed through the top of the trochanter and straight down the long axis of the femur. (J213.1.w1)
    • A small incision can be made in the skin overlying the proximal aspect of the greater trochanter. (B606.17.w17)
    • Insert the needle anterograde, parallel to the femur's long axis and into the medullary cavity. (B602.14.w14)

Technique
  • Restraint
    • This procedure can be carried out in the conscious animal or under general anaesthesia. (B600.3.w3, B601.2.w2)
    • Sedation should be used for this procedure. (B602.14.w14)
  • Selection of the site
    • Select an appropriate bone for catheterisation (see the sites above).
    • Direct penetration of the bone marrow cavity is easier in the humerus or the tibia of the rabbit than the femur. (B600.3.w3)
  • Preparation
    • Intraosseous catheterisation should be performed under sterile surgical conditions. (B606.17.w17)
      • Clip the fur overlying the selected bone and then aseptically prepare the skin. (B600.3.w3, B601.2.w2, B602.14.w14, J29.15.w2)
      • Sterile gloves should be worn for carrying out the procedure. (B602.14.w14)
    • Note: aseptic technique is essential to avoid the risk of osteomyelitis. (J213.1.w1)
  • Analgesia
    • If the procedure is carried out in the conscious animal then it is necessary to infiltrate local anaesthetic (lidocaine (lignocaine)) into the local tissues and the periosteum. (B600.3.w3, B601.2.w2, J29.15.w2)
  • Select an appropriate needle
    • The needle used should be based on the materials available and on the size of the bone. (B601.2.w2) 
      • A 20 to 22 gauge needle around half the length of the bone, i.e. 4 to 6 cm (1.5 to 2.5 inches). (B600.3.w3, B606.17.w17)
      • Suitable needle sizes vary from 1 to 1.5 inches in length and 18 to 23 gauge depending on the size of the patient. (B602.14.w14)
    • Spinal needle (B601.2.w2, B606.17.w17)
      • This is the best option because the needle is strong and able to penetrate the bone; also, the stylet prevents the bone clogging the bone. (B600.3.w3)
    • A standard hypodermic needle (with a smaller gauge needle or a piece of orthopaedic wire acting as a stylet). (B600.3.w3, B601.2.w2, B602.14.w14, B606.17.w17)
      • If using a standard hypodermic needle, attach a syringe filled with sterile physiological saline to the needle. The syringe acts as a handle, and if the plunger is held steady keeping the fluid under pressure as the needle goes through the bone, it prevents the needle from becoming blocked. (V.w125)
    • Commercially available intraosseous needle (B601.2.w2, B602.14.w14)
  • Catheterisation
    • Use the needle to bore through the cortex of the bone and into the bone marrow cavity (a sudden lack of resistance is felt as the needle penetrates the marrow cavity). (B600.3.w3, B601.2.w2)
    • Throughout this procedure, the needle must be kept straight and aligned in the direction of the selected bone. (B600.3.w3, B601.2.w2)
    • Once the medullary cavity has been penetrated, It may be necessary to slightly redirect the needle to push it down the cavity. (B600.3.w3)
    • If the needle is moved from side to side it will create a larger hole than is necessary and therefore fluid leakage can occur around the injection site. (B600.3.w3)
    • Remove the stylet (where appropriate). (B601.2.w2)
  • Confirm correct placement of the needle
    • It is important to check that the needle tip is actually in the medullary cavity and not penetrating or pushing up against the cortex. (B600.3.w3)
      • Attach a syringe to the needle and aspirate bone marrow to confirm correct placement. (B600.3.w3)
      • Flush the catheter with heparinised saline to ensure it is patent. (B601.2.w2, B602.14.w14, B606.17.w17)
      • If there is any doubt then confirm the position by radiography. (B600.3.w3, B601.2.w2)
    • If the needle is not in the correct place then it should be withdrawn and the procedure should be attempted again on a different bone. (B600.3.w3)
  • Attach a male adapter (B602.14.w14)
  • Secure the catheter
    • The catheter can be sutured or glued in place. (B600.3.w3)
  • Protect the catheter
    • The site should be bandaged to restrict the mobility of the leg and to maintain cleanliness. (B601.2.w2)
    • Antiseptics and dressings can be used to protect the catheter and decrease the risk of infection. (B600.3.w3, B602.14.w14)
    • An Elizabethan collar may be needed to prevent the rabbit from removing the catheter. However, ideally these should not be used in stressed or very sick rabbits. (B602.14.w14)

Maintenance of the catheter
  • Aseptic technique must always be used when medication or fluids are administered via the intraosseous catheter. (B601.2.w2)
  • Flush the catheter with heparinised saline 
    • Flush the catheter between uses or three times a day if it is not being used regularly. (B601.2.w2)
    • Heparin should be used to flush the catheter every four to six hours. (B600.3.w3)
  • Remove the catheter after 72 hours and repeat the procedure at a different site if intraosseous catheterisation is still indicated. (B600.3.w3, B601.2.w2) A light dressing and some antiseptic should be applied to the site after the catheter has been removed. (B600.3.w3)
Appropriate Use (?)
Indications
  • Administration of drugs or fluids in situations where it is impossible or difficult to obtain intravenous access, e.g. juveniles, or rabbits in cardiogenic shock. (B600.3.w3, B601.2.w2, B602.14.w14, B606.17.w17, J29.15.w2, J213.1.w1, J213.9.w1)
  • Some veterinarians prefer this route of fluid therapy to intravenous infusion and so use it routinely. (B600.3.w3)

Note: The different sites for intraosseous catheterisation vary in their ease of use.

  • Greater trochanter of the humerus
    • This is the easiest site for intraosseous catheterisation. (B600.3.w3)
  • Greater trochanter of the femur 
    • This is the least satisfactory site for administering intraosseous fluid therapy because there is a well-developed trochanteric fossa that can be seen when the femur is viewed caudally. The intraosseous catheter must pass through this fossa (penetrating three layers of cortical bone) to enter the medullary cavity. (B600.3.w3)
Notes
  • Manufacturer's data sheet recommendations should be followed as to the recommended route and rate of drug administration (subcutaneous, intramuscular, intravenous).
  • Dirty needles and syringes must be disposed of properly (needles always into a properly marked sharps container. (D249.w10)
Complications/ Limitations / Risk
  • In wild lagomorphs
    • While most veterinary procedures described for use in domestic rabbits can also be used in wild lagomorphs, it is much more likely that sedation will be required to carry out such procedures in wild lagomorphs.
  • Clipping
    • Take care not to damage the delicate skin during clipping or plucking. (J213.9.w1)
Contraindications
  • Bones that are:
    • poorly mineralised (B600.3.w3, B601.2.w2)
    • fractured (B600.3.w3, B601.2.w2)
    • immature with active growth plates (B600.3.w3)
    • diseased (B600.3.w3)
Disadvantages
  • There is a risk of introducing infection into the bone resulting in osteomyelitis. (B600.3.w, 3J213.1.w1)
    • Careful aseptic technique minimises this risk. (B600.3.w3, aseptic technique is essential to avoid the risk of osteomyelitis. (J213.1.w1))
  • The administration rate can be slow. (B600.3.w3)
    • Use of multiple sites allows faster overall administration. (B600.3.w3)
Limitations
  • This procedure is painful and either should be performed under general anaesthesia or local anaesthetic should be used. (B606.17.w17)
Equipment / Chemicals required and Suppliers
  • Appropriate-sized sterile needle or catheter.
    • A 20 to 22 gauge needle around half the length of the bone, i.e. 4 to 6 cm (1.5 to 2.5 inches). (B600.3.w3, B606.17.w17)
    • Suitable needle sizes vary from 1 to 1.5 inches in length and 18 to 23 gauge depending on the size of the patient. (B602.14.w14)
      • Spinal needle (B601.2.w2, B606.17.w17, J29.15.w2)
        • This is the best option because the needle is strong and able to penetrate the bone; also, the stylet prevents the bone clogging the bone. (B600.3.w3, J29.15.w2)
      • A standard hypodermic needle (with a smaller gauge needle or a piece of orthopaedic wire acting as a stylet). (B600.3.w3, B601.2.w2, B602.14.w14, B606.17.w17, J29.15.w2)
      • Commercially available intraosseous needle (B601.2.w2, B602.14.w14)
  • Local anaesthetic solution e.g. Lidocaine (Lignocaine).
  • Sterile gloves.
  • Required medication.
Expertise level / Ease of Use
  • This procedure should only be carried out by an individual with appropriate clinical training and practical experience.
Cost / Availability
  • Equipment used for intraosseous catherisation is relatively inexpensive and readily available.
  • Cost of medications.
Legal and Ethical Considerations In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery." (See: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons).

Use of Drugs (Medication):

  • Many drugs are not registered for use in lagomorphs and care should be taken in their use, with proper regard for possible toxic effects. Consideration should be give to relevant legislation regarding the use of drugs.
  • In any country, drugs are unlikely to be specifically licensed for use in non-domestic mammals. 
    • In Europe the prescription cascade must be followed, and the client's informed consent should be obtained, whenever a drug is used which is not licensed for use in a given species. (B284.5.w5)
    • In the UK, guidelines regarding the use of drugs are set out in the Royal College of Veterinary Surgeons Guide to Professional Conduct 2000: (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Choice of Medicinal Products).
Author Nikki Fox BVSc MRCVS (V.w103)
Referee Debra Bourne MA VetMB PhD MRCVS (V.w5); Molly Varga BVetMed DZooMed MRCVS (V.w125)
References B600.3.w3, B601.2.w2, B602.14.w14, B606.17.w17, J213.1.w1, J213.9.w1

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